Field of the Invention
The present invention relates to a zoom lens and an image pickup device including the same and, in particular, to a zoom lens and an image pickup device suitable for use in image pickup optical systems of a digital still camera, a video camera, a security camera, a broadcast camera, a film camera, and the like.
Description of the Related Art
In recent years, an image pickup optical system included in an image pickup device including a solid-state image pickup element is desired to have high optical characteristic to an extent equivalent to supporting a high resolution solid-state image pickup element and further be capable of taking images at various magnifications.
A zoom lens for a security camera is desired to have a super wide angle of view and a small F-number. Furthermore, imaging of a subject in twilight time and nighttime uses not only visible light but also near infrared light. Accordingly, a degree of out-of-focus is required to be reduced in a wide wavelength range including near infrared light to visible light. Furthermore, the size of entire system is required to be small.
As a zoom lens configuration satisfying such demand, configurations of negative-lead type zoom lenses are known that include a lens unit having a negative refractive power arranged on the most object side. As to negative-lead type zoom lenses, Japanese Patent Application Laid-Open No. 2005-134887 and Japanese Patent Application Laid-Open No. 2011-175174 disclose zoom lenses that include, in sequential order from the object side to the image side: a first lens unit having a negative refractive power; and a second lens unit having a positive refractive power, wherein both the lens units are moved to perform zooming.